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Full text of "A trial of three chemicals as rodent repellents in direct seeding"

Historic, archived document 



Do not assume content reflects current 
scientific knowledge, policies, or practices. 



.4 

i 



REST ffiSEA 

U.S.DEBIRTMENT OF 

FOREST SERVICE 
lEST 

m STAT 

STEPHEN N. WYCKDFF, Director 






February h s 1953 



No. 8li 



A TRIAL OF THREE CHEMICALS AS 



mwm REP ELLENTS W MTaglN^ 



G H. Schubert, Forester, 
Division of Forest Management Research 

/ a mnftnfO and, to a lesser extent., red 

Sodium fluoroacetate (compound "1080 rodent repe ileot S 

lead and zinc phosphide, have been suggested for » » Stanislaus 
in direct seeding On J^^*^ 1 ^ chemicals appears effec- 

!^ rl ??!gnenS ev^n SoSS are effective as poisons, 
vive a>-' - rjp*'- 1 --*- 

Compound .1080", equivalent to S percent ^f t ^ .^w^wae' 
was added^o asphalt and to dowax Ca "—"J* 'S* ««• ^ d 

used as the carrier for zinc phosphide and for respectively, 

at the rites of S and 10 percent by weight o : the were tJien 

Water was added to each mixture to form a ^ P^«; handljJlg and to 
rolled in the repellent and allowed to dry to rac 
insure maximum retention of the chemical. 

A total of $ spots were planted w^h sugar pine - ^ 
of 5 seed per spot. Approximately one-iifth of the s^ ^ Qr _ 
tected with cone screens, to determ^e ^ effect o£Jh^ ^ spots, 
germination. Untreated seeds were planted on one nunw 

2 percent of the unscreened spots wxth coated seed, were ^ Qf ^ 
fafl of i*e first year, and this dropped to 1 percent at^ ^ 
second year (Table 1). In «*W'^^ f ^ first growing season, 
coated seeds averaged 88 percent at the end of V* control 

and 80 percent b 1 



1/ Mr. Joseph Keyes retired f, 
wilrtVife Service, cooperated in ^he test by |reparing 

^dteting 

* MAINTAINED &T BERKELEY, CALIFORNIA. IN COOPERATION 





Treatments 



: Screened j Unscreened : Screened : Unscreened 



5 percent "1080" in asphalt 

5 percent "1080" in dowax 

5 percent zinc phosphide in dowax 

10 percent red lead in dowax 

Average, all coated seed 

Control 



100 
85 
80 
93 
88 
80 



5 


2 
2 
4 



85 
80 
80 
71 
80 
75 



2 


2 
1 
2 



Since rodents destroyed practically all seeds left unscreened, 
germination can be compared only on the screened seed spots. Seed treated 
with 5 percent in asphalt had the highest germination (54 percent). 

Those treated with 10 percent red lead in dowax had the lowest germination 
(43 percent), . The untreated control seed germinated 48 percent. Those 
treated with 5 percent "1080" in dowax and with 5 percent zinc phosphide 
in dowax germinated 44 and 48 percent respectively. These differences 
are not statistically significant. The chemicals apparently neither 
repressed nor aided germination. 

Empty seed coats, scattered in and around the seed spots indicated 
that rodents --^white -footed mice (Peromyscus spp), chipmunks (Eutamias 
spp), and ground squirrels ( Cite ; 1 lus sp'p)-- and not birds had destroyed 
the seed. Evidently amounts of the coating substances too small to be 
repellent or lethal had been ingested by the rodents. A poison or repel- 
lent which could penetrate the seed coat and be absorbed in the endosperm 
without being detrimental to the embroyo would probably be a more effective 
means of rodent control. The substance, Tetr amine, under current investi- 
gation by the U. S, Fish and Wildlife Service™^, is believed to possess 
these properties. Tetr amine is currently being tested by the California 
Forest and Range Experiment Station in the Douglas -fir area in California. 



2/ Spencer, Donald A, and Nelson B Kverno. 1952, Research in 
rodent control to promote reforestation by direct seeding „ U. S. Fish 
and Wildlife Service. Progress Report No. 3, 74 p» 



2~